1. Field of the Invention
The present invention generally relates to a water content detecting device for a diaper to encourage prompt changing of the same when wet. In its particular aspects, the present invention relates to a device containing a sensing unit for detecting the water content in any type of diaper such as a cloth-made diaper and a paper made disposable diaper and an informing unit for transmitting the information regarding the water content to a remote place.
2. Description of the Prior Art
Recently, the number of aged people has increased owing to the progress of medical science, and also the number of bed ridden people has tended to increace simultaneously. In nursing hospitals for such aged people, it is estimated that at least 30 percent of the patients are ridden. For nursing such patients, the treatment of excrements has been a serious problem. It is obvious that providing easy treatment for at least urine would lighten the distress and burden on the patients and nursing people. Conventionally, two manners have been commonly used for such urine treatment. One manner is a diaper treatment using a diaper or napkin to absorb the excreted urine. The other manner is a continuous urine excretion treatment system using an urethral catheter such as balloon catheter which must be always outfitted to the patient.
The above mentioned diaper treatment will be discussed in detail as the present invention is related to this treatment. In hospitals or nursing homes, the time for changing diapers of patients is fixed at specified intervals, since the nurse does not know the urination pattern of all the patients. However, with this manner, some of the patients may be left with a wet diaper for a long time causing discomfort and pain owing to a diaper rash, cooling, bed sores and the like.
In order to determine the urination pattern of such patients, a particular method to detect the water content in urine has been provided. The method for detecting the water content by means of change in electric conductivity of electrodes such as an electric wire installed in the diaper, has been applied. Further, a structure of a capacitor is formed in the diaper so that the degree of wetness can be determined by detecting the change in electrostatic capacity of the capacitor. These water content detecting methods have been proposed in our prior inventions (Japanese Patent Application for Utility Model No. 58-202267, No. 57-71558 and Japanese Patent Applications No. 59-128237, No. 59-128238 and No. 59-143649).
These methods can provide comfort to the patients since wet diapers can be changed by the nurse or nursing person informed of the wet condition of the diaper through electrical means. However, these methods require prior assembly of the electric wire or the metal layers to form the capacitor in the diaper. The patients may be inconvenienced since only such specially made diapers, particularly disposable diaper, are effective. Further, many aged people prefer to use a conventional cloth type diaper capable of reuse.
The electric wire type water content detecting diaper often causes troubles owing to breaking, disconnecting or twisting by the movement of the patients or babies or whoever is wearing this type diaper. Further this type of diaper can not detect the degree of wetness of the diaper without being checked directly by a nursing person.
On the other hand, the capacitor type water content detecting diaper can detect the degree of wetness of the diaper by measurement of the change of electrostatic capacitance. In the above described conventional invention, the electrostatic capacitance is measured by an AC bridge method referred in JIS (Japanese Industrial Standard) C-5102. This AC bridge method always requires an AC power source, so that this method consumes a relatively large amount of electrical energy. Additionally the change of electrostatic capacitance is detected by a coil having the value of inductance corresponding to the frequency of the AC power source. This makes the detecting circuit complicated, thereby increasing its manufacturing cost.